It emits a stinking cloud composed of millions of nascent microscopic organisms, each possessing a fragment of predatory sentience.

Toxicrene

Reach, deathtouch
Hypertoxic Miasma — All lands have "{T}: Add one mana of any color" and lose all other abilities.

Warhammer 40,000 Commander

If a permanent has an ability that causes itself to be a land, such as that of Ashaya, Soul of the Wild, that ability will apply to it even though it loses that ability due to Toxicrene. This is because type-changing effects are always applied before any effects that add or remove abilities. It will still have "{T}: Add one mana of any color" and lose all other abilities.